Accurate wind measurements are essential in various applications and for various industries. In the wind industry, the miscalculation of wind resources for electricity generation is an industry wide problem. Industry estimates suggest that wind developers are inaccurately predicting the pre-construction energy yield estimates of wind farms by ten percent on average globally: Site selection is the first crucial step in the practical development of these farms and investors decide whether or not to invest on the basis of wind resource assessment reports. Typically, these reports require a rigorous assessment of site-specific wind conditions over a twelve-month period before any significant investment proceeds. Industry experts suggest that existing wind measurement technology is not up to the task of providing sufficient data for an accurate assessment of a site's wind resource potential. A second problem identified is with the ongoing operation of so-called horizontal axis wind turbines (HAWT) once installed. Misalignment of the yaw angle of a HAWT with the incident wind is apt to cause significant variation in power output (as well as inducing additional stress loads on the critical components of the turbines causing premature wear and tear and accelerating the maintenance cycle). For example, a yaw angle misalignment of ±15° will lead to a 5-6% annual energy loss. Turbine misalignment is a common phenomenon particularly in lower wind speed conditions where yaw angle misalignments of up to 30% are common across the industry.
These problems are exacerbated when HAWTs are located in complex terrains. Trials conducted in Warwick have shown that the likely or predicted energy output from building-mounted micro-wind turbines are prone to overestimation by factors of between 15 and 17.
Current approaches to addressing the problems of wind resource measurement may be generally categorized into discreet families of devices as follows: Mechanical anemometry (cup and vane); active remote sensing technology (SoDAR and LiDAR); hot-wire anemometry; sonic anemometry, and; pitot-tube anemometry and subdivisions thereof.